Do you guys agree with this statement?

[Jeff Seal]

Re: Do you guys agree with this statement?

There are many examples of both types and quite a few that disprove any conclusive theory regarding any type of manufacture being superior.

We will examine a few:

Blackface Fender - Using "turret" board construction (PTP), these amps are considered as the pinnacle of Fender design's. They have a very low failure rate, rather they are reaching the age of simply needing a "restoration" having served many useful years. 40 yrs+ is a pretty impressive "first life", and it really doesn't require much to get another 50 yrs out of these.

Silverface Fender's (later ones)- Using almost exactly the same circuit's as the BF Fender, and the same quality or better components (still PTP). Many of these rapidly failed or malfunctioned at an alarming rate and are prone to "ghosts, oscillations, etc." even when every single component checks out perfect!
Why?.... it is well known the "wire dress" in these are so inferior to the BF's, Fender adopted the policy of wrapping single wires around bundles and grounding one end of it to prevent problems. What is "wire dress"?? Very simply how the wires are run inside the amp from one point to another. Since many of these wire's are carrying the greatly amplified signal in excess of 380v, even in the preamp!, how close they are to other wires, the chassis and even transformers can cause problems and a compromise of tone. This coupled with the bias circuit change in these left many new buyers disappointed. The simpler circuits like the Champ were less prone to problems than the complex Twin circuits, but then again who gigs with a Champ.?
I had a SF Twin in the shop two weeks ago with a "chirping" tremolo, all components checked out fine, but the problem persisted until I moved one wire 1/8" away from another wire running right underneath it!...(no joke!)

So even the exact same method of construction can work flawlessly or can be prone to problems... Another PTP amp we'll look at is a Hiwatt!...

If you have ever wanted to see the "ultimate" in construction, look no further than these bad boy's, the inside is spotless!.....However, in order to maintain this perfect "appearance", some wire's were unnecesarily run much longer than needed, creating a "very" slight additional noise..... of course Hiwatt's were never really played soft enough for anyone to even notice!!...

These, and older Traynors, remain as the finest examples of "clean" PTP layout...very few will disagree..

PCB based amps that excel are much simpler to find, but even they are prone to being categorized into "PCB only", which is not true...

First, PCB is very simply "Printed Circuit Board", whereas PTP is "Point to Point".... just in case you didn't know! Unlike PTP, which is pretty straight forward in construction, (components and wires to connect them)
PCB, which has "traces" or "paths" embedded into a fiber board, either on one side or both. These "traces" cannot move and are consistent from one to another, thus ensuring any "problems" will be exclusive to all, while "proven" successes are equally guaranteed from amp to amp. This ensures consistency, but that's not always ideal! PCB's come in differing forms...

1. PCB with "flying" leads to connect the board to external components..
2. PCB with "flying" leads to connect some components, while having some directly mounted to the PCB itself.
3. PCB with all components directly connected to the PCB, only using wires to connect external components or even other PCB's together, and even variations to some extent of all of these.

4. "Double sided" PCB is one that has "traces" or "paths" printed on both sides of the PCB.

(more coming..) hold on...

[Jeff Seal]

Re: Do you guys agree with this statement?

The order listed above poses a "double edged sword", although #1 is the least expensive to design and easiest to make, it still requires substaintally more labor to assemble a final product. It's success rate is the highest among the PCB amps when it comes to "potential" problems...

Best Example: Marshall Super Lead (not the RI's)

#2 above represents probably the most common PCB designs in the last 30 yr's with the possibility of more "potential" problems than #1, but at less cost to produce...

Best Examples: Marhsall JCM800's..which have controls solder mounted to the PCB with the tube sockets using wires to connect them. Mesa/Boogies which have tube sockets solder mounted and using wires to connect the controls. Variations are easily found even within these camps!

#3 above reperesents most current production amps, and while the least expensive to produce, they are the most likely to have problems....

Best Example: Marshall TSL/DSL line, since all external controls, jacks and tube sockets are solder connected directly to individual PCB's. Plus the fact that cheaper and smaller components are being used during manufacture.

#4 is actually a "variable" and examples can be easily found covering the whole range of the previous three spectrums. These cost the most to design and prototype, but when done right are found in even the most expensive amps...

How an amp is "made" is not an indication of how well it performs, Diezel Herberts are one huge PCB, but Peter Diezel simply designed them to "stay built" and they are killer amps... Matchless is a great example of PTP construction, but they won't overdrive like a Diezel!

My personal favorite and most trusted amp is my 1989 Marshall 2210, which is PCB.....However, my own hand made amps are PTP and can easily accomodate "changes" based upon the customer's request. Since no two people usually share an opinion on the "best amp", I've found it best to be flexible.... which PCB isn't....

So draw your own conclusions......

....as always more info than was probably required....

Jeff Seal

[ErikH]

Re: Do you guys agree with this statement?

Great info, Jeff. Thanks for sharing.

BTW, how'd your shop fare in the hurricane? Everything's ok I'm hoping.

[More-Gear-Than-Skill]

Re: Do you guys agree with this statement?

i suppose the marketing quip is much like the whole "class A" thing, sounding like "first class", sounding like "the best" sounding like "you're worth it" sounding like advertising companies....

[aleclee]

Re: Do you guys agree with this statement?

Another consideration is production volume. For designs where mass production isn't in the cards, it's not worth the effort to design a PCB, especially since PCB layout is a somewhat different skill set than lead dress.

Unfortunately, automated PCB layout doesn't do such a great job on tube amps because the programs are designed to optimize layout and can create some funky capacitance and/or inductance issues in high voltage audio circuits.

[joelap]

Re: Do you guys agree with this statement?

Plus, I don't know of anyone who would want to make a P2P triple channel amp with separate EQ's for each.

Jeff Seal does it all the time

Looks like he already got here

[Amateur]

Re: Do you guys agree with this statement?

Do you agree or disagree and why?

"PCB boards are better than point to point." "Point to point handwired is good for marketing."

I think it depends on who is selling the amp and whom he is selling to. A PCB circuit is more compact and faster to manufacture for mass production, hence cheaper and faster to produce. Definitely a good marketing and selling point if you are a PCB circuit manufacturer trying to sell your product to the amp manufacturer or the amp manufacturer trying to sell it to the retail or public.

On the other hand, the PTP circuit is much more easier to make modifications and diagnose if something had gone wrong. You can change a single component easily if you want to. You usually have to detach the PCB to get to the flip side when you try to diagnose or follow a circuit, which is very combersome and dangerous when you have the power on. A nightmare for the service tech.

If the amp is all solid state, then it probably will last long provided that its components do not suffer early failure. A PCB will have its advantage in this case.The heat that are generated from the tubes in a tube amp will definitely do a number on its components and some of them may fail earlier than they should. You can easily spot that component and change it if it is PTP. It is more difficult spot the failed component if you have a PCB and you usually end up changing the whole board because it is not practical if not impossible to change that component.